Faster flu vaccine production process based on insect cells

15 December 2009

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A researcher at Wageningen University, Netherlands has developed an alternative process for producing large quantities of
safe and effective vaccines at twice to four times the usual speed.

The process is based on using insect cells in bioreactors instead of
fertilised chicken’s eggs, which have a limited availability, and could
result in shortages of flu vaccines becoming a problem of the past.

The prompt availability of sufficient suitable vaccine is always a
problem when facing the outbreak of a flu epidemic. At the moment, it
takes three to six months to produce a vaccine to counter a new strain
of flu virus using chicken’s eggs. Moreover, there is no possibility of
expanding production capacity in the event of a pandemic as the limited
availability of fertilised chicken’s eggs needed for production
inevitably becomes an insurmountable problem.

Researcher Manon Cox’s new process
demonstrates that it is possible to make a vaccine available in
commercial quantities within 45 days. The new production method makes
use of a baculovirus that multiplies only inside insect cells, and which
cannot spread in vertebrates. The insect cells produce huge quantities
of so-called HA proteins, which mobilise the immune system into fighting
the flu virus.

The aspect that most slows down the production of vaccine according
to the conventional method is the need for fertilised chicken eggs.
Furthermore, this creates extra problems if the flu virus is also
capable of infecting birds (as was the case in the Netherlands in 2003),
as the egg production often grinds to a halt.

In addition, the vaccines
produced are not suitable for people with an egg allergy. The new
production process using insect cells can be used on a large scale, at
all times and simultaneously at various locations throughout the world.
The process can easily be adapted to new influenza strains and enhance
pandemic preparedness.

Meanwhile, the new production process has already been put through
clinical trials involving three different strains of flu virus in 460
healthy people. None of the test subjects injected with the vaccine
developed symptoms of flu, while 4.6% of those taking part in the
control group contracted the disease naturally.

Three follow-on studies
involving approximately 3,000 people showed no striking or frequent
side-effects. The vaccine also appears to protect people from influenza
viruses that have undergone genetic changes and in more than 50% of
cases, it results in better antibody production than the flu vaccines
currently available.

Vaccines for the flu virus contain the HA protein (haemagglutinin)
which, once in the bloodstream, puts the body in a state of high alert.
The protein also stimulates the production of flu-specific antibodies.
The same protein is found on the surface of a flu virus. When a
vaccinated person encounters a flu virus , the antibodies produced
attach to the proteins on the surface of the virus and inactivate the
virus.